N-Isocyaniminotriphenylphosphorane (Ph3PNNC) as an Efficient Reagent for the Synthesis of Fully Substituted 1,3,4-Oxadiazoles from 3-Phenyl-2-Propynoic Acid,Secondary Amines and Aromatic Bis-Aldehydes

Abstract

Reactions of N-isocyaniminotriphenylphosphorane (Ph₃PNNC) with aromatic bis-aldehydes (isophthalaldehyde and terphthalaldehyde) in the presence of 3-phenyl-2-propynoic acid and secondary amines proceed smoothly at room temperature and in neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions were observed.     

Four-Component Synthesis of Disubstituted 1,3,4-Oxadiazoles from N-Isocyaniminotriphenylphosphorane,Phenylacetylenecarboxylic Acid,Chloroacetone Derivatives,and Primary Amines

The 1:1 imine intermediate generated by the addition of primary amine to chloroacetone derivatives is trapped by N-isocyaniminotriphenylphosphorane in the presence of phenylacetylenecarboxylic acid, leading to the formation of the corresponding iminophosphorane intermediate. Disubstituted 1,3,4-oxadiazole derivatives are formed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. The reactions were completed in neutral conditions at room temperature. The disubstituted 1,3,4-oxadiazole derivatives were prepared in excellent yields.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis of 2-amino-5-(5R-1,2,4-oxadiazolyl-3)-1,3,4-oxadiazoles

The interaction of 2-amino-1,3,4-oxadiazole-5-carboxamidoxime with nitriles in the presence of ZnCl₂ and HCl or with trichloroacetic anhydride affords 2-amino-5-(5R-1,2,4-oxadiazolyl-3)-1,3,4-oxadiazoles. Their reactions with N-nucleophiles have been studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2100–2103, December, 1993.     

Synthesis of 1,3,4-thiaza- and 1,3,4-oxazaphosphol-2-lines based onN-phosphorylated (thio)ureas

The reactions ofO-phenyl chloromethylisothiocyanatothioxophosphonate andO-phenyl chloromethylisocyanatophosphonate with trimethylsilyldiethylamine lead to the formation of 1,3,4-thiazaphosphol-2-ine and 1,3,4-oxazaphosphol-2-ine, respectively. Phosphorylation ofN-methyl-N-phenyl-N,N-bis(trimethylsilyl)urea withO-phenyl chloromethylchlorophos phonate gives 1,3,4-diazaphospholidin-2-one.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1857–1859, July, 1996.     

2-(4-吡啶基)-5-芳基-1,3,4-噁二唑的合成与表征

以碳酸钠为缚酸剂,4-吡啶甲酰肼与苯甲酰氯反应得N,N＇-二酰基肼,后者在POCl3作用下脱水环化成2-（4-吡啶基）-5-芳基-1,3,4-噁二唑,其结构经^1H NMR,IR,MS和元素分析确认,并对其裂解途径进行了探讨。     

2-芳基-5-(4-硝基苯甲酰氨基)-1,3,4-噻二唑的合成

以芳甲酰肼和对硝基苯甲酰氯为主要原料, 合成出了10个酰氨基硫脲化合物5a～5j, 其中有6个(5d, 5f～5j)为新化合物. 在无需任何酸性催化剂条件下, 将制得的酰氨基硫脲在DMF中加热回流直接脱水关环合成出了9个2-芳基-5-(4-硝基苯甲酰氨基)-1,3,4-噻二唑化合物6a～6i, 其中7个(6b～6d, 6f～6i)为新化合物. 利用IR和1H NMR证明了化合物5存在两种异构体. 目标产物的结构通过IR, 1H NMR和元素分析进行了表征.     

Synthesis, Crystal Structure and Biological Activity of N-(2,6-Difiuorobenzoyl)-N'-[5-(4-trifiuoromethylphenyl)-1,3,4-thiadiazol-2-yl] ure

The title compound N-(2,6-difluorobenzoyl)-N'-[5-(4-trifluoromethylphenyl)-1,3,4-thiadiazol-2-yl]urea(C17H9F5N4O2S, Mr = 428.34) has been synthesized by the reaction of 2-amino-5-(4-trifluoromethylphenyl)-l,3,4-thiadiazole with 2,6-difluorobenzoyl isocyanate, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 10.7316(13), b = 10.5617(13), c = 16.037(2) (A), β =106.408(2)°, V= 1743.6(4) (A)3, Z = 4, Dc = 1.632 g/cm3, μ = 0.260 mm-1, F(000) = 864, the final R = 0.0599 and wR = 0.1420 for 3467 observed reflections with I ＞ 2o(Ⅰ). The urea group, which adopts a planar configuration mediated by the intramolecular N-H…O hydrogen bond, is nearly coplanar with the thiadiazole and 4-trifluoromethylbenzene rings. The title compound was found to exhibit good fungicidal activity against Rhizoctonia solani and Botrytis cinerea.     

5-(4,6-Diphenyl-2-pyrimidinyl)-1,3,4-oxadiazole-2-thione with Some C-Electrophiles and N-Nucleophiles

5-(4,6-Diphenyl-2-pyrimidinyl)-1,3,4-oxadiazole-2-thione reacted with haloalkanes or their derivatives containing side chain oxo group to give S-alkylated compounds. Aminomethylation and acylation of the thione yielded N₍₃₎-derivatives. Treatment of the title compound with hydrazine hydrate in butanol resulted in 4-amino-5-(4,6-diphenyl-2-pyrimidinyl)-1,2,4-triazole-3-thione via a recyclization reaction. Reaction of the title compound with hydrazine hydrate or phenylhydrazine in dioxane led to formation of the corresponding thiocarbohydrazides. The latter in the presence of a base were cyclized to 4-amino-1,2,4-triazole-3-thiones.     

The Reaction of 5-Aryl(hetaryl)-2-aroylmethylthio-1,3,4-oxadiazoles with Aryldiazonium Tetrafluoroborates

5-Aryl(hetaryl)-2-aroylmethylthio-1,3,4-oxadiazoles behave as CH acids and readily react with aryldiazonium tetrafluoroborates at the active methylene group to give azo coupling products. The spectroscopic properties of the compounds synthesized have been studied.     

新型N-(5-烷基-1,3,4-噻二唑-2-基)-1-[(杂芳基)甲基]-5-甲基-1H-1,2,3-三唑基-4-甲酰胺的合成与生物活性

为了寻找新型高效低毒的农药先导化合物, 采用1-[(杂芳基)甲基]-5-甲基-1H-1,2,3-三唑基-4-甲酰氯与2-氨基-5-烷基-1,3,4-噻二唑的缩合反应, 合成了8种未见文献报道的目标化合物, 其结构经IR, 1H NMR和元素分析确证, 部分化合物还经MS的进一步证实. 初步的生物活性测试结果表明, 部分目标化合物在100 mg/L浓度下对双子叶植物(油菜)显示出中等的除草活性和一定程度的杀虫活性(250 mg/L).     

新型N-(5-烷基-1,3,4-噻二唑-2-基)-11[(杂芳基)甲基]-5-甲基-1H-1,2,3-三唑基-4-甲酰胺的合成与生物活性

为了寻找新型高效低毒的农药先导化合物,采用1-[(杂芳基)甲基]-5-甲基-1H-1,2,3-三唑基-4-甲酰氯与2-氨基-5-烷基-1,3,4-噻二唑的缩合反应,合成了8种未见文献报道的目标化合物,其结构经IR,1H NMR和元素分析确证,部分化合物还经MS的进一步证实.初步的生物活性测试结果表明,部分目标化合物在100 mg/L浓度下对双子叶植物(油菜)显示出中等的除草活性和一定程度的杀虫活性(250 mg/L).     

Synthesis of 3-(3-Acetyl-5-aryl-2,3-dihydro-1,3,4-oxadiazol-2-yl)chromones

A method is proposed for the synthesis of 3-(3-acetyl-5-aryl-2,3-dihydro-1,3,4-oxadiazol-2-yl)chromones which consists of the conversion of 3-formylchromones to aroylhydrazones and their subsequent heterocyclization using acetic anhydride.     

N- And S-Alkylation of 3-(1-Aadamantyl)-4-methyl-1,2,4-triazole-5-thiol and 2-(1-Adamantyl)-1,3,4-oxadiazole-5-thiol

ABSTRACT

-The reaction of 3-(1-adamantyl)-4-methyl-1,2,4-triazole-5-thiol 1 with certain 2-aminoethyl chlorides in alkaline medium yielded a separable mixture of the S-(2-aminoethyl) derivatives 2 and the N-(2-aminoethyl) derivatives 3. Meanwhile, alkylation of 2-(1-adamantyl)-1,3,4-oxadiazole-5-thiol 4 with 2-aminoethyl chlorides under the same conditions yielded only the S-alkyl derivatives 5. Interaction of 4 with primary or secondary amines and formaldehyde solution yielded the corresponding N-aminomethyl derivatives in high yields.     

Synthesis of 3-(5-Aryl-1,3,4-oxadiazol-2-yl)chromones

A general method was proposed for the synthesis of 3-(5-aryl-1,3,4-oxadiazol-2-yl)chromones starting from 3-formylchromone. This aldehyde yields acylhydrazones, from which the corresponding unstable nitrile imines are generated. These intermediates undergo intramolecular 1,3-dipolar cycloaddition.     

(N-Isocyanimino)triphenylphosphorane as an Efficient Reagent for the Synthesis of 1,3,4-Oxadiazoles from 3-Substituted Benzoic Acid Derivatives

The reaction of 3-substituted benzoic acid derivatives with (N-isocyanimino) triphenylphosphorane proceeds smoothly at room temperature to afford corresponding 1,3,4-oxadiazoles via an intramolecular aza-Wittig reaction in excellent yields under neutral conditions.     

Reaction of 4-Methylene-1,3-dioxolan-2-ones with Hydrazines

The structure of the products of the reaction of 4-methylene-1,3-dioxolan-2-ones with hydrazines is a function of the structure of the starting hydrazine. 1,3,4-Oxadiazin-2-one derivatives are obtained from hydrazine hydrate. 3-Arylaminooxazolidin-2-ones are obtained from monoarylhydrazines, while mixtures of these derivatives are obtained from aliphatic monoalkylhydrazines.     

N-[5-(4-三氟甲基苯基)-1,3,4-噻二唑-2-基]-N′-芳酰基脲的合成、结构及其生物活性

通过2-氨基-5-(4-三氟甲基苯基)-1,3,4-噻二唑与芳酰基异氰酸酯反应, 合成了14种新的芳酰基脲, 它们的结构用红外光谱、核磁共振氢谱和元素分析进行了表征, 并且采用X-射线单晶衍射分析方法测定了化合物2l的结构．初步的生物活性试验表明, 部分标题化合物具有优良的植物生长调节活性.     

Synthesis of the Ethyl Esters of 4-(3-Pyridyl)- and 4-(4-Pyridyl)-2-oxobutenoic Acids

We have developed a method for the synthesis of ethyl 4-(3-pyridyl)- and 4-(4-pyridyl)-2-oxobutenoates by condensation of 3-pyridinecarbaldehyde and 4-pyridinecarbaldehyde monohydrate respectively with ethyl pyruvate, esterifiction of the target acids, and hydrolysis of the corresponding ethyl ester ketals in the presence of FeCl₃·6H₂O.     

N-(5-对三氟甲基苯基-1,3,4-噻二唑-2-基)-N''''-芳酰基硫脲的合成及生物活性

用2-氨基-5-对三氟甲基苯基1，3，4-噻二唑与芳酰基异硫氰酸酯反应，合成了14种新的标题化合物（3a-3n），其的结构经1^H NMR，IR和元素分析确证。室内初步的生物活性测定试验表明，部分标题化合物具有良好的植物生长调节活性，其中3e，3g和3m的生长素活性更好。     

Synthesis,characterization and anticancer evaluation of 2-(naphthalen-1-ylmethyl/naphthalen-2-yloxymethyl)-1-[5-(substituted phenyl)-[1,3,4]oxadiazol-2-ylmethyl]-1H-benzimidazole

In the present study o-phenylenediamine and naphtene-1-acetic acid/2-naphthoxyacetic acid were used as a starting material through a series of steps and 2-(naphthalen-1-ylmethyl/Naphthalen-2-yloxymethyl)-1H-benzimidazol-1-yl]acetohydrazide 5a, 5b were obtained. In the first series 1,3,4-oxadiazole derivatives have been synthesized from Schiff base of the corresponding hydrazide i.e. 2-[2-(naphthalen-1-ylmethyl)-1H-benzimidazol-1-yl]acetohydrazide 5a by using Chloramin-T. In the second series 1,3,4-oxadiazole has been synthesized from 2-{2-[(naphthalen-2-yloxy)methyl]-1Hbenzimidazol-1-yl}acetohydrazide 5b by using phosphorous oxychloride and aromatic acid. These compounds were evaluated by IR, NMR, Mass spectrometry, elemental analysis and finally in vitro anticancer evaluation was carried out by NCI 60 Cell screen at a single high dose (10–5 M) on various panel/cell lines. One compound 7c was found to be the most active on breast cancer cell line and compounds 4b and 7d were moderately active.